Bus-bar



March 8, 1938. R. W.. SHOEMAKER 2,110,743

BUS-BAR Filed May 29, 1935 2 Sheets-Sheet 2 Patented Mar. 8, 1938 UNITED STATES PATENT ort-ICE- 'BUS-BAR Richard W. Shoemaker,

Woodbury, Conn., aS-

signor to The Chase Companies, Incorporated, Waterbury, Conn., a corporation Application May 29, 1935, `Serial No. 24,061

U 2 Claims.

of the tubular bus-bars aresubjected to very high collapsing strains, especially under short circuit conditions. 'In a 60cycle alternatingcurrent system, the collapsing force would be of a pulsating or vibratory character exerted times per second. Composite bus-bars, as generally heretofore made, have required that their component parts be securely clamped together at short intervals, but, owing tothe mechanical vibrating eilect of the current passing therethrough, such fittings have been 'susceptible to loosening under the vibrating force which under some conditions may rise as high as 5,000 lbs. per linear foot of bus-bar.

One of the objects of the present lnventionis" to provide a ventilated tubular bus-bar which will be substantially proof against the disintegrating effects of the vibratory stresses set up by heavy currents flowing therethrough.

A further object is to provide a ventilated tubular bus-bar having superior rigidity.

Another object is to provide a tubular bus-bar `in which the character of the Ventilating-means is such as to have a minimum eiect upon the conductivity of the bus-bar.

A still further object of the present invention is to provide an arrangement whereby the busbar will be effectively cooled by air-currents without unduly reducing its conductivity or i mechanical strength.

a With the above and other objects in View, as

will appear to those skilled in the art from the following, considered in conjunction with the accompanying drawings and appended claims, the present invention includes all features within the range of the said claims.

In the accompanying drawings: A

Fig. 1 is a broken plan view of a portion of a bus-system composed of bus-bars embodying the present invention;

Fig. 2 vis a broken perspective view of one form which a tubular integral ventilated bus-bar may assume in accordance with the present in:1 vention;

Fig. 3 is a longitudinal sectional view thereof, taken on the line 3--3 of Fig. 2;

Fig. 4 is a transverse sectional view taken on the line 4--4 of Fig. 2;

Fig. 5 is a similar view taken on the line 0-5 of Fig. 2;

Fig. 6 is a broken perspective View of an intei are formed integrally. 'Ihe bus-bar is preferably gral tubular bus-bar having slot-like ventilatingports; and

Fig. 7 .is a transverse sectional view taken on the line iI-II of Fig. 10.

The particular bus-bar 20 illustrated in Figs. 1 to 5 inclusive of the accompanying drawings is of rectangular form in cross-section and includes a iiat top-wall 2 l, a iiat bottom-wall 22 and complementary flat side-walls 23 and 24, all of which Cri of drawn copper or other metal of high electroconductivity.

Adjacent its point of juncture with the integral side-wall 24, the top-wall 2l of the bus-bar is formed with a longitudinal series of spacedapart air-egress ports 25, each of which is sepa--I rated from its neighbor by an integral web .26* completing the one-piece perimeter of the said ports.

The bus-'bar is also formed in its bottom-wall 22 with a longitudinally-extending series of airingress ports 26 which are located longitudinally intermediate the air-egress ports 25 and also laterally displaced with respect to the latter, so as to be located adjacent the junction point of the said bottom-wall 22 with its integral side-wall 23. Like the ports 25, the air-ingress ports 26 are separated from each other by integral webs 26", the ends of which latter complete the integral walls of the said ports 26.

As the bus-bar becomes heated due to the passage of an electric current therethrough, air will be drawn, by convection, inwardly through the air-ingress ports' 26 in the bottom-wall 22 and will flow both longitudinally and laterally, and will ultimately exit upwardly through the airegress ports 25 in the top-Wall 2|, as indicated particularly well in Figs. 3 to 5 inclusive.

By the staggered relationship of the air-ingress ports 26 and the air-egress ports 25, a maximum cooling effect is obtained with a minimum amount of cutting away of the metal, inasmuch as the air entering through the ingress-ports 26 is forced to travel both longitudinally and laterally before it can escape from the interior of the bus-bar, thus wiping, so to speak, a maximum mount of the internal surface of the tube.

Furthermore, by staggering the egreM-ports 25 and the ingress-ports 26 longitudinally with reu spect to each other, the conductivity of the busbar is cut down to a lesser extent than would the case were the said ports located transversely in line. In other words, despite the fact that the tube is perforated both top and bottom, .conductivity of the tube at any given transverse point is cut/down only by the amount of metal removed by the production of but one port. The mechanical strength of the bus-bar is also least affected by the staggering ofthe ports, as described.

When heavy alternating currents are owing through the bus-bar, the webs 25* and 26* effectively prevent relative movement between the metal on the respective opposite sides of the ports 25 and 26, thus obviating one of the objections inherent in. prior bus-bar structures.

In Figs. 6 and 7 is shown an integral drawn tubular bus-bar 3l, also of rectangular form in cross-section and including a top-wall 35, a bottom-wall 3B and complementary side-walls 31 and 3|, all formed integrally with each other.

Instead of perforating the topand bottomwalls, the bus-bar 34 is perforated in its sidewalls in staggered relationship. Thus, the sidewall 31 is provided with a series of longitudinallyextending slot-like air-egress ports I9, located in the said side-wall adjacent the point of the junction of the latter with the top-wall 35 and having `interposed between them lintegral webs 3P. At a materially-lower level than the level of the ports n, the wall Il of the bus-bar is formed with a series of longitudinally-extending slot-like air-ingress ports 4I, preferably located in the said side-wall at point adjacent the junction of the latter with he integral bottom-wall 36 and spaced from each other by integral webs Ml.

By reference to Fig. 7 in particular, it will be seen that the egress-ports 30 and the ingressports 4I, by virtue of their vertically-staggered relationship, cause air entering the said ingressports to wipe against a large area of the interior surface of the tube before escaping through the egress-ports 39.

It will be noted that while a given pair of the ports I9 and ll are vertically staggered in displaced relationship with respect to each other, they are substantially laterally in line, and for this reason it is preferred to secure the necessary port area by making the said ports of slot-like form extending longitudinally of the bus-bar, so that the reduction in cross-sectional area of the bus-bar at a given point is kept at a minimum.

All of the bus-bars herein illustrated are extremely economical of installation and effective in operation, owing largely to the integral character of the structure. Thus, especially under short-circuit conditions, the pulsating collapsing forces (which are applied and released 120 times per second in a 60-cycle system) have no effect in loosening one wail with respect to another. Furthermore, by the integral character of the webs between any given pair of ports of the same series, not only is superior mechanical strength obtained, but clamping-fittings, usually required in great numbers, may largely, if not entirely, be dispensed with.

It will be obvious, without further illustration, that the various ports may be of 'various shapes and spacings. Bus-bars of rectangular form in cross-section are much to be preferred in present practice, for the reason that they provide suitably-located flat faces against which connectingplates for branches (both vertical and horizontal) may be secured.

'I'he invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

l. A one-piece wrought tubular bus-bar designed and adapted for current-carrying bussystems and composed of high electro-conductive metal and of rectangular form Vin cross-section and having substantially-flat integral top, bottomand side-walls; the said rectangular busbar being formed in a lower wall-portion with a longitudinal series of spaced-apart air-ingress ports, and also formed in an upper wall-portion with a longitudinal series of spaced-apart airegress ports, the individual air-ingress ports bcing separated from others of the series thereof by webs of metal formed integrally with the metal of the rectangular bus-bar, and the individual air-egress ports of the series thereof being also separated from companion ports by integral webs; certain of the said series of airingress portsbeing located laterally intermediate the longitudinal center-line of the upper-wall portion of the bus-bar and a side-edge of such wall portion and laterally staggered with respect to certain of the said series of air-egress ports and the staggered relationship being such that the upper-wall portion of the bus-bar is substantially solid in the areas immediately above the said ingress-ports, thus causing air entering the former to wipe laterally across the interior surface of the rectangular bus-bar before exit through air-egress ports.

2. A bus-bar system .comprising a plurality of one-piece wrought tubular bus-bars and composed of high electro-conductive metal and of rectangular form in cross-section and having substantially-flat integral top, bottomand sidewalls; the said rectangular bus-bars being formed in a lower wall-portion with a longitudinal series of spaced-apart air-ingress ports, and also formed in an upper wall-portion with a longitudinal series of spaced-apart air-egress ports, the individual air-ingress ports being separated froml others of the series thereof by webs of metal formed integrally with the metal of the rectangular bus-bar, and the individual air-egress ports of the series thereof being also separated from companion ports by integral webs; certain of the said ports being located laterally intermediate the longitudinal center-line of the upper-wall portion of the bus-bar and a side-edge of such wall portion and staggered relative to others of said ports in directions both laterally and longitudinally of the bus-bar and the staggered relationship being such that the upper-wall 'portion of the blu-bar is substantially solid in the areas immediately above the said ingress-ports, thus causing air entering ingress ports to travel both laterally and longitudinally through the interior of the rectangular bus-bar and exit through air-egress ports.

RICHARD W. SHOEMAKER. 

